Process of making aldehydes



- These obJects are accomplished by vaporizing the gram mol. per minute. Air was introduced into sponding aldehyde.

Patented July 12,1938 2,123,520 1 UNITED STATES PATENT orr ca A PROCESS OF MAKING ALDEHYDES Dale Friend Babcock, Eimhurst, and James Herbert Werntz, Marshallton, Del.,,as signors to E.

L-du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 20, 1934, Serial No. 749,174

' 23 Olaims. (Cl. 260-138) This invention relates to the oxidation of long chamber was maintained at a temperature of chain primary alcohols to corresponding alde- 530 C. An analysis of the converted liquid prodhydes and more particularly it pertains to the not indicated that 23% of dodecyl alcohol had oxidation of primary straight-chain alcohols havbeen converted to dodecyl aldehyde without the 5 ing 8, 10, 12, and 14 carbon atoms with a silver formation of significant quantities of acid or 5 catalyst. ester.

This invention has as an object the prepara- Example III tion of aldehydes from long-chain primary Octyl alcohol was pumped into the preheater cohols. Other objects will appear hereinafter. as dgscribed in Example I, at the rate of 0A0v alcohol, mixing the vapor with oxygen or air, and passing the gaseous mixture over a silver conf i i f g gi g ggg 'f gi zg gg' fg fi taining catalyst at a temperature sufflcient to per minute. The resulting air-alcohol mixture cause the oxidation of the alcohol to the correwas preheated to The preheated gases r then ass h h the c tal ic chamber The following examples are given 1n order to gg f f: gg g g i teiltperature of more completely describe the invention: said chamber was maintained at 560 C. The

. Example I converted liquid products were found to contain tyl aldehyde corresponding to a conversion of A mixture of prnnary alcohols containing 8, 10, 0c

12, and 14 carbon atoms, obtained by the car- Losses to cal-hon dmxlde and other-undeboxylic hydrogenation of coconut oil and known g decomposition products g lgss in commerce as crude dodecyl alcohol, was pumped into a preheater consisting of a steel FTJ E E ZiLZ S E Z 11 255 tube 1.5 inches inside diameter and3 feet long, 0 e o g c m p y y 5 rm '1 or 2 and packed with glass rings at the rate of 0.20 whether the i cliams be no a gram per minute Air was introduced into branched. The invention is particularly adapted to the treatment of those primary alcoholshavmig g fiagi :5 gggggfi gi gg fig gg ggi ing eight or more carbon atoms. A particularly per minute. The resulting airs-alcohol mixture 2 2 52 31 5:2 l 1 31:: 12.12%??? t3:

was preheated to 290 C. These preheated gases pp 1 d b h b0 were then passed through a'catalyst chamber mixture prepare. y t 8 car Kym hydrogenation of an essentially saturated natconsisting of a copper tube 1.5 .inches inside ural oil such as coconut oil. In place of the air, diameter by 10 mches long and containing 100 0 gen or an oxygen and an inert gas ture silver gauze disks made from 20 by 20 mesh a 35 gauze. The catalyst chamber was maintained fiz gg i gg' 1 z s zgzg fii fgggfig i fig at temperatura/bf 530 to 575 during the of oxygen to alcohol is between 0.25 and 0.66.

reaction. An analysis of the converted liquid t i 0 The temperature in the catalytic chamber durproduc ndlcated that 2 of the crude dodecyl ing the reaction should be maintained above 400 40 40 alcohol had been converted to a mixture of aldehydes without the formation of significant quanf preferably withm the range to titles of esters, acids or other polymerized mate- 600 The alcohol may or may not contain rials. Theefiiuent gas contained 3 to 4% carbon ten or water vapor may or may not be added dioxide and less than 05% to the vapors to be preheated. This modifica- I 1 y tion serves chiefly to provide a better means for H controlling the converter temperature.

Pure dodecyl alcohol was pumped into the pre- The mixture of air and alcohol Vapor. is heater described in Example I at the rate of heated to a e perature abov t boiling p 0.16 gram mol. per minute. Air was introduced of the alcohol but substantially below the teminto the preheater at the 'rate of 0.40 gram mol. perature of h reac ion hamber- P eferably 50 per minute or at an oxygen rate of 0.08 gr the preheated temperature is such that a heatmol. per minute. The resulting air-alcohol mfxbalance is maintained under the conditions of t'ure was preheated to' 290 C. These preheated operation. For an operation such as in the exgases were then passed through the catalyst amples above, this temperature is about 250 to chamber described in Example 1,. while that 300 (3., but the most favorable preheating tem- 55 perature will depend on the heat balance and on the scale of operation.

The catalyst used in the applicants process should be silver or a silver containing alloy and may be in any form or shape, provided suflicient surface is exposed to the gas. The preferred catalyst is silver gauze made up in the manner as described in Example I. It has been known for many years that methanol could be converted to formaldehyde and more recently ethanol has been converted to acetaldehyde by a similar catalytic oxidation process. It wasnot at all apparent that high molecular weight alcohols could be subjected to the drastic treatment of heating them to 500 to 600 C. in the presence of oxygen and obtain a satisfactory yield of the desired aldehyde.

An alternate method of converting a primary alcohol to the aldehyde is by catalytic dehydrogenation. This process is not only inferior to the present proposed process in that the catalyst cost is high and a large amount of heat must be added to the system which necessitates a more complicated apparatus, but also the dehydrogenation process produces relatively large quantities of ester as a by-product. As stated, the quantity of ester formed by this oxidation process is small.

The above description and specific examples are illustrative only and are not to be considered as limitingthe scope of the invention. Any variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

. We claim:

1. The process of preparing the corresponding aldehydes from long-chain primary alcohols which comprises passing a mixture containing a long-chain primaryalcohol and oxygen over a silver containing catalyst at a temperature in excess of 400 C.

2. The process of preparing aldehydes of at least eight carbon atoms from the corresponding alcohols which comprises passing a mixture containing a primary alcohol of at least eight carbon atoms and oxygen over a silver containing catalyst at a temperature in excess of 400 C.

3. The process of making aldehydes which comprises passing a mixture containing a longchain primary alcohol and oxygen over a silver gontaining catalyst at a temperature of 500 to 4. The process according to claim 3, characterized in that the molecular ratio of oxygen to alcohol is between 0.25 and 0.66.

5. The process according to claim 3, characterized in that the long-chain primary alcohol contains at least eight carbon atoms.

6. The process according to claim 3, characterized in that the catalyst consists of a multiple number of pieces of silver gauze.

'7. The process of making aldehydes which comprises passing a gaseous mixture containing a long-chain primary alcohol and air over a silver containing catalyst at a temperature of 500 to 8. The process of making aldehydes which comprises preheating a mixture containing a long-chain primary alcohol and oxygen and passing said preheated gaseous mixture over a silver containing catalyst at a temperature of 500 to 600 C. i

9. The process of making aldehydes which comprises preheating a mixture containing a longchain primary alcohol and oxygen to a temhydes which comprises passing a mixture of long-chain primary alcohols and oxygen over a silver containing catalyst at a temperature of 500 to 600 C.

12. The process of making a mixture of aldehydes which comprises passing a mixture of long-chain primary alcohols, having even-numbered carbon atoms from 8 to 14, inclusive, and air, over a silver containing catalyst at a tern perature of 500 to 600 C.

13. The process of making a mixture of aldehydes which comprises preheating a mixture of long-chain primary alcohols, having even-numbered carbon atoms from 8 to 14; inclusive, and air in a molecular ratio of oxygen to alcohol of about 0.5 to a temperature of about 290 C., and passing said preheated gases over a catalyst consisting of a multiple number of pieces of silver gauze at a temperature of 530 to 540 C.

14. The process of making lauryl aldehyde which. comprises passing a gaseous mixture of lauryl alcohol and oxygen over a silver containing catalyst at a temperature of 500 to 600 C.

15. The process of making lauryl aldehyde which comprises preheating a gaseous mixture of lauryl alcohol and oxygen and passing. the preheated gases over a silver containing catalyst at a temperature of 500 to 600 C. a

16. The process according to claim 14, characterized in that the molecular ratio of oxygen to alcohol is between 0.25 and 0.66.

17. The process of making lauryl aldehyde which comprises preheating a mixture of lauryl alcohol and air of a molecular ratio of oxygen to alcohol of about 0.5 to a temperature of about 290 C., and passing said preheated gases over a catalyst consisting of a multiple number of pieces of silver gauze at a temperature of about 530 C.

18. The process of making octyl aldehyde which comprises passing a gaseous mixture of octyl alcohol and oxygen overa silver containing catalyst at'a temperature of 500 to 600 C.

19. The process of making octyl aldehyde which comprises preheating a gaseous mixture of octyl alcohol and oxygen and passing the preheated gases over a silver containing catalyst at a temperature of 500 to 600 C.

20. The process according to claim 18, characterized in that the molecular ratio of oxygen to alcohol is betwen 0.25 and 0.66.

21. The process of making octyl aldehyde which comprises preheating a gaseous mixture of octyl alcohol and air of a molecular ratio of oxygen to alcohol of about 0.5 to a temperature of about 250 C., and passing said preheated gases over a catalyst consisting of a multiple number of pieces of silver gauze at a temperature of about 560 C.

22. The process of making aldehydes which comprises passing a mixture containing a long chain primary alcohol and oxygen over a silver alyst at a temperature of 500 to 600 C. and at substantially atmospheric pressure, the molecular ratio of oxygen to alcohol being between 0.25

containing catalyst at a temperature of 500 to 600 C. and at substantially atmospheric pressure.

23. The process of making aldehydes which comprises passing a mixture containing a long chain primary alcohol of at least eight carbon atoms and oxygen over a silver containing catand 0.66. 

